Project description:Since the 1800s, the only known vector of Borrelia recurrentis has been the body louse. In 2011, we found B. recurrentis DNA in 23% of head lice from patients with louse-borne relapsing fever in Ethiopia. Whether head lice can transmit these bacteria from one person to another remains to be determined.
Project description:BackgroundBorrelia recurrentis is the causative agent of louse-borne relapsing fever, endemic to the Horn of Africa. New attention was raised in Europe, with the highest number of cases (n = 45) reported among migrants in 2015 in Germany and sporadically from other European countries. So far only one genome was sequenced, hindering the development of specific molecular diagnostic and typing tools. Here we report on modified culture conditions for B. recurrentis and the intraspecies genome variability of six isolates isolated and cultured in different years in order to explore the possibility to identify new targets for typing and examine the molecular epidemiology of the pathogen.Methodology/principal findingsTwo historical isolates from Ethiopia and four isolates from migrants from Somalia (n = 3) and Ethiopia (n = 1) obtained in 2015 were cultured in MPK-medium supplemented with 50% foetal calf serum. Whole DNA was sequenced using Illumina MiSeq technology and analysed using the CLC Genomics Workbench and SPAdes de novo assembler. Compared to the reference B. recurrentis A1 29-38 SNPs were identified in the genome distributed on the chromosome and plasmids. In addition to that, plasmids of differing length, compared to the available reference genome were identified.Conclusions/significanceThe observed low genetic variability of B. recurrentis isolates is possibly due to the adaptation to a very conserved vector-host (louse-human) cycle, or influenced by the fastidious nature of the pathogen and their resistance to in vitro growth. Nevertheless, isolates obtained in 2015 were bearing the same chromosomal SNPs and could be distinguished from the historical isolates by means of whole genome sequencing, but not hitherto used typing methods. This is the first study examining the molecular epidemiology of B. recurrentis and provides the necessary background for the development of better diagnostic tools.
Project description:Iron overload has been well recognized to cause oxidant-mediated cellular/tissue injury; however, little is known about the effects of iron overload on the blood coagulation system. We encountered an unexpected bleeding tendency in rats fed a high-iron diet in a set of studies using iron-modified diets. In this study, we investigated the mechanism of hemorrhagic diathesis induced by dietary iron overload in rats. Six-week-old F344/DuCrlCrlj male rats were fed a standard (containing 0.02% iron) or a high-iron diet (containing 1% iron) for 6 weeks and were then sampled for hematological, blood biochemical, coagulation, and pathological examinations. Serum and liver iron levels increased in rats fed the high-iron diet (Fe group) and serum transferrin was almost saturated with iron. However, serum transaminase levels did not increase. Moreover, plasma prothrombin time and activated partial thromboplastin time were significantly prolonged, regardless of the presence of hemorrhage. The activity of clotting factors II and VII (vitamin K-dependent coagulation factors) decreased significantly, whereas that of factor VIII was unaltered. Blood platelet levels were not influenced by dietary iron overload, suggesting that the bleeding tendency in iron-overloaded rats is caused by secondary hemostasis impairment. In addition, hemorrhage was observed in multiple organs in rats fed diets containing more than 0.8% iron. Our results suggest that iron overload can increase the susceptibility of coagulation abnormalities caused by latent vitamin K insufficiency.
Project description:Human louse-borne relapsing fever occurs in sporadic outbreaks in central and eastern Africa that are characterized by significant morbidity and mortality. Isolates of the causative agent, Borrelia recurrentis, were obtained from the blood of four patients during a recent epidemic of the disease in southern Sudan. The glpQ gene, encoding glycerophosphodiester phosphodiesterase, from these isolates was sequenced and compared with the glpQ sequences obtained from other relapsing-fever spirochetes. Previously we showed that GlpQ of Borrelia hermsii is an immunogenic protein with utility as a serological test antigen for discriminating tick-borne relapsing fever from Lyme disease. In the present work, we cloned and expressed the glpQ gene from B. recurrentis and used recombinant GlpQ in serological tests. Acute- and convalescent-phase serum samples obtained from 42 patients with louse-borne relapsing fever were tested with an indirect immunofluorescence assay (IFA) and an enzyme-linked immunosorbent assay (ELISA) that used whole cells of B. recurrentis and with immunoblotting to whole-cell lysates of the spirochete and Escherichia coli producing recombinant GlpQ. The geometric mean titers of the acute- and convalescent-phase serum samples measured by IFA were 1:83 and 1:575, respectively. The immunoblot analysis identified a high level of reactivity and seroconversion to GlpQ, and the assay was more sensitive than the whole-cell IFA and ELISA using purified, recombinant histidine-tagged GlpQ. Serum antibodies to GlpQ and other antigens persisted for 27 years in one patient. We conclude that assessment of anti-GlpQ antibodies will allow serological confirmation of louse-borne relapsing fever and determination of disease prevalence.
Project description:In an effort to understand how a tick-borne pathogen adapts to the body louse, we sequenced and compared the genomes of the recurrent fever agents Borrelia recurrentis and B. duttonii. The 1,242,163-1,574,910-bp fragmented genomes of B. recurrentis and B. duttonii contain a unique 23-kb linear plasmid. This linear plasmid exhibits a large polyT track within the promoter region of an intact variable large protein gene and a telomere resolvase that is unique to Borrelia. The genome content is characterized by several repeat families, including antigenic lipoproteins. B. recurrentis exhibited a 20.4% genome size reduction and appeared to be a strain of B. duttonii, with a decaying genome, possibly due to the accumulation of genomic errors induced by the loss of recA and mutS. Accompanying this were increases in the number of impaired genes and a reduction in coding capacity, including surface-exposed lipoproteins and putative virulence factors. Analysis of the reconstructed ancestral sequence compared to B. duttonii and B. recurrentis was consistent with the accelerated evolution observed in B. recurrentis. Vector specialization of louse-borne pathogens responsible for major epidemics was associated with rapid genome reduction. The correlation between gene loss and increased virulence of B. recurrentis parallels that of Rickettsia prowazekii, with both species being genomic subsets of less-virulent strains.
Project description:We described a series of imported cases of Crimean-Congo Hemorrhagic Fever (CCHF) in Istanbul and investigated the genetic diversity of the virus. All the suspected cases of CCHF, who were applied to the health centers in Istanbul, were screened for CCHF virus (CCHFv) infection by using semi-nested Polymerase Chain Reaction (PCR) following RT-PCR. Simultaneous blood samples were also sent to the national reference laboratory in Ankara for serologic investigation. In 10 out of 91 patients, CCHFv was detected by PCR, and among 9 out of 10, anti-CCHFv IgM antibodies were also positive. Clinical features were characterized by fever, myalgia, and hemorrhage. The levels of liver enzymes, creatinine phosphokinase, and lactate dehydrogenase were elevated, and bleeding markers were prolonged. All the cases were treated with ribavirin. There was no fatal case. All the strains clustered within the same group as other Europe/Turkey isolates.
Project description:BackgroundHyalomma marginatum and Hyalomma rufipes are two-host tick species, which are mainly distributed in southern Europe, Africa and middle-eastern Asia. They are well-known vectors of Crimean Congo hemorrhagic fever (CCHF) virus and other viruses as well as Rickettsia aeschlimannii. In recent years, these tick species have been found sporadically in Germany, but they do not belong to the autochthonous tick fauna in Germany.MethodsTicks with unusual morphology were collected and sent from private persons or public health offices to involve institutions for morphological identification and further testing. All ticks identified as Hyalomma spp. were tested using molecular detection methods for CCHF virus, Rickettsia spp., Coxiella burnetii and Coxiella-like organisms, Babesia spp. and Theileria spp.ResultsThirty-five ticks with an unusual appearance or behaviour were reported to us during summer-autumn 2018. For 17 of them, the description or photos implied that they belong to the hard tick genus Hyalomma. The remaining 18 ticks were sent to us and were identified as adult Hyalomma marginatum (10 specimens) or adult Hyalomma rufipes (8 specimens). All ticks tested negative for CCHF virus, Coxiella burnetii, Coxiella-like organisms, Babesia spp. and Theileria spp. The screening for rickettsiae gave positive results in 9 specimens . The Rickettsia species in all cases was identified as R. aeschlimannii.ConclusionsThese results show that exotic tick species imported into Germany were able to develop from the nymphal to the adult stage under appropriate weather conditions. Fifty percent of the ticks carried R. aeschlimannii, a human pathogen, while CCHF virus or other pathogens were not detected. Imported Hyalomma ticks may be the source of exotic diseases acquired in Germany.
Project description:An outbreak of acute febrile syndrome associated with coagulopathy and severe pancytopenia occurred in cattle grazing in paddocks with high infestation by Adiantopsis chlorophylla. The administration of the plant to a calf reproduced the same signs and lesions seen in spontaneous cases. Similar syndromes are caused by ptaquiloside from bracken fern. Traces of the ptaquiloside-like molecule caudatoside were detected together with 0.03-0.24 mg/g of it's degradation product pterosin A, in dry fronds of the plant. In conclusion, A. chlorophylla is a cause of hemorrhagic diathesis in cattle.